Whole river ecology: spatial scale and heterogeneity in the ecology of running waters
Hildrew, A. G.
There are two separable ways to study the ecology of large rivers. First, one can adopt the approach of stream ecologists, who have often stressed small-scale patchiness in both the biota and the physicochemical environment. The technology needed for big rivers is different but the ideas are the same. Second, one can address population and community ecology at the truly larger scale of the whole river in which the full physical hierarchy of large fluvial systems, including headwaters and the floodplain, comes into play. They are complex habitats, but I try to match the spatial and temporal scales of environmental variation with the life histories, mobility and interactions of the inhabitants. The possible importance to river ecology of new theoretical developments on the role of spatial heterogeneity is addressed and the importance of physical refugia from disturbance is stressed. I argue that a multi-scale approach to "whole river ecology" is needed for both scientific and practical (management) purposes.